I can’t use Python console commands in my custom functions

Question

I’m trying to make my custom function:

import bpy

def custom_function():
    active = bpy.context.active_object

    # to set cursor location to active object
    bpy.ops.view3d.snap_cursor_to_selected()

custom_fuction()

It's a really simple one, but even that gives me an error:

  ret = _op_call(self.idname_py(), None, kw)

Error:

RuntimeError: Operator bpy.ops.view3d.snap_cursor_to_selected.poll() failed, context is incorrect

I quite don’t get it. Why doesn’t it work?

Answer 1

This operator is only available in the context of the 3D viewport. It means if you're executing it in any other context, it will fail.

You either need to swap areas before and after the execution :

old_type = bpy.context.area.type
bpy.context.area.type = "VIEW_3D"
bpy.ops.view3d.snap_cursor_to_selected()
bpy.context.area.type = old_type

Or you can use an override. Note that you have to have at least one 3D viewport editor open in the interface for it to work.

area = next((a for a in bpy.context.screen.areas if a.type == "VIEW_3D"), None)
if area is not None:
    bpy.ops.view3d.snap_cursor_to_selected({"area": area})

Or starting with Blender V3.2+ :

area = next((a for a in bpy.context.screen.areas if a.type == "VIEW_3D"), None)
if area is not None:
    with bpy.context.temp_override(area=area):
        bpy.ops.view3d.snap_cursor_to_selected()